Ditching the draft tube on a Y-block.

October 16, 2009

So back in my truck’s heyday, there really weren’t too many concerns about the environment. Motors dripped, and puked oil smoke and it was just fine. Now we have closed systems and try to avoid pushing out pollutants whenever possible.

So my 292 was equipped with something called a draft tube. This thing basically allowed burned oil to escape the engine while running into the atmosphere. What happens is that this stuff will build pressure inside of a closed block and other nastiness will ensue. Plus there is big ol’ o-ring on mine that was just shot out and instead of keeping the oil in and letting the pollutants out, it was just dripping all over the place. A PCV system is also better for the engine since it aids in remove the stuff that is a direct cause of engine sludge. So if I was gonna have to work on it, might as well use a better system.

Here is what I bought to do the change.

A PCV gasket from the HELP! section that you find in most of the major parts places – part no. 42052 It is a 1 1/8″ mount hole

A PCV valve – I used Fram part no. FV295. It would allow you to pull but not push air though.

And of course some hose to fit these all together.

So here is the draft tube as it came from the factory.

Not elegant, but it worked for 50 years.

Now off it went. You can see in the next two images where oil pools up before flowing back into the block and the mounting screws. Now there is a seal at that point to keep the oil from spilling out. Unfortunately my gasket was shot out and was just letting drip.

Just two screws so it was actually pretty easy to do.

Now off it went.

And here is what the block looks like under there.

I know, I really could use a steam bath for the engine. But it’s a driver, not a looker.

Now I just need a template for the opening. And the original gasket is a perfect solution for that.

I used some of the same plate I had from making the fuel pump block off for this too. Plenty thick and it is free.

And after a bit of cutting and grinding…

And a few holes for the mounting screw and…

Perfect!

Now I didn’t take any pictures of this, so I am going to have to jump ahead here. I pulled the valve cover off. drilled the hole with a hole saw and after good deburring, was able to put the new grommet in. Plumbed the hose to my air filter and was done.

It took a few days because of laziness, but all in all it probably took no more than a couple of hours to accomplish. And now there are no more drips on the driveway. And no more puffing from the tube. I really didn’t have an issue with too much pressure as it was, so as of yet, there has not been any negatives.

Fingers crossed I won’t find any either.

Well shit, I spoke too soon. I posted this entry to a car site called The Jalopy Journal. While I got kudos for the simplicity of the change over, I was dinged because I patched in my vacuum wrong. After getting better idea on my misstep I went back and revised my setup.

On my intake there is a 5/8′ plug in my manifold. I needed vacuum from there. Luckily I had a 3/8 to 5/8 fitting and was able to put that to use. So Instead of going into my air cleaner, I now have it plumbed to my manifold for the extra vacuum. Here is how it looks now.